Vehicle control method and apparatus

ABSTRACT

In an apparatus, an attention region defining unit defines an attention region near a blocking obstacle upon the blocking object being determined to be located between the own vehicle and the target object based on the results of the detection operations. The blocking object at least partly blocks a view from the own vehicle. A determiner determines whether the target object is located in the attention region. An obtaining unit obtains, upon it being determined that the target object is located in the attention region, a detection history of the target object by the object detection sensor before the target object is determined to be located in the attention region. An adjuster adjusts, based on the obtained detection history, a predetermined procedure of recognition for the target object upon it being determined that the target object is located in the attention region.

CROSS REFERENCE TO RELATED APPLICATION

This application is based on and claims the benefit of priority fromJapanese Patent Application No. 2017-014332 filed on Jan. 30, 2017, thedisclosure of which is incorporated in its entirety herein by reference.

TECHNICAL FIELD

The present invention relates to methods and apparatuses for performinga collision safety control task to thereby activate a safety deviceinstalled in an own vehicle.

BACKGROUND

Conventionally, vehicle control apparatuses perform a known pre-crashsafety (PCS) control task as an example of a collision safety controltask. The PCS control task activates at least one safety deviceinstalled in an own vehicle to thereby mitigate and/or avoid collisiondamage between the own vehicle and objects, such as other vehicles,pedestrians, or road structures located ahead in the travellingdirection of the own vehicle.

For example, Japanese Patent Application Publication No. 2014-109943,which will be referred to as a published patent document, discloses anexample of a vehicle control apparatus configured to perform such a PCScontrol task.

The vehicle control apparatus disclosed in the published patent documentis configured to address a target object, such as a pedestrian, whichsuddenly runs in front of an own vehicle from a region at least partlyblocked by a stopped vehicle when viewed from the own vehicle.

Specifically, the vehicle control apparatus disclosed in the publishedpatent document has an object recognition condition, such as apedestrian recognition condition, and performs an object recognitiontask to thereby determine that there is a target object, such as apedestrian, in front of the own vehicle upon the target objectsatisfying the predetermined object recognition condition.

In particular, the vehicle control apparatus disclosed in the publishedpatent document relaxes a level of the predetermined object recognitioncondition for a region at least partly blocked by a blocking obstacle,such as a stopped vehicle, located in front of the own vehicle to belower than a level of the predetermined object recognition condition forthe same region in the case where there are no blocking obstacles, suchas stopped vehicles, detected in front of the own vehicle.

For example, the vehicle control apparatus disclosed in the publishedpatent document performs the object recognition tasks based onrespective captured images in front of the own vehicle. The vehiclecontrol apparatus determines whether the number of at least one ofpedestrian image patterns being recognized in the captured images duringthe object recognition tasks has reached a predetermined number. Then,the vehicle control apparatus determines that there is a pedestrian infront of the own vehicle when determining that the predeterminedpedestrian recognition condition is satisfied upon the number of atleast one of pedestrian image patterns being recognized in the capturedimages during the image recognition tasks having reached thepredetermined threshold number.

In particular, the vehicle control apparatus reduces the thresholdnumber to thereby relax the predetermined pedestrian recognitioncondition for the region at least partly blocked by the stopped vehiclelocated in front of the own vehicle if the stopped vehicle is detectedin front of the own vehicle.

This condition relaxation enables a pedestrian located in the region atleast partly blocked by the stopped vehicle to be recognized faster.

SUMMARY

The vehicle control apparatus disclosed in the published patent documentrelaxes the level of the predetermined object recognition condition fora region at least partly blocked by a blocking obstacle, such as astopped vehicle, located in front of the own vehicle without exception.

For this reason, if a target object, which has been already captured bythe vehicle control apparatus, moves into the region at least partlyblocked by the blocking obstacle, the vehicle control apparatusdisclosed in the published patent document relaxes the level of thepredetermined object recognition condition for the blocked region. Thismay result in the target object, which is located in the blocked region,being recognized faster, although it is unnecessary to recognize thetarget object faster. This is because it is possible to predict anaccurate movement trajectory of the target object that has been alreadydetected by the vehicle control apparatus.

Unnecessary faster recognition of the target object, which has beenalready captured by the vehicle control apparatus, may result inunnecessary activation of at least one safety device installed in theown vehicle.

In view of these circumstances, the present disclosure mainly seeks toprovide methods and apparatuses for controlling a vehicle, each of whichis capable of properly activating at least one safety device if there isa blocking obstacle located ahead in a travelling direction of thevehicle.

A first exemplary aspect of the present disclosure is an apparatus to beinstalled in an own vehicle equipped with an object detection sensorthat repeatedly performs a detection operation for detecting objectsaround the own vehicle. The apparatus is configured to recognize, basedon results of the detection operations, a target object in accordancewith a predetermined procedure, and perform at least one of a collisionavoidance operation and a damage mitigation operation for the ownvehicle with respect to the recognized target object. The apparatusincludes an attention region defining unit configured to define anattention region near a blocking obstacle upon the blocking object beingdetermined to be located between the own vehicle and the target objectbased on the results of the detection operations. The blocking object atleast partly blocks a view from the own vehicle. The apparatus includesa determiner configured to determine whether the target object islocated in the attention region, and an obtaining unit configured toobtain, upon it being determined that the target object is located inthe attention region, a detection history of the target object by theobject detection sensor before the target object is determined to belocated in the attention region. The apparatus includes an adjusterconfigured to adjust, based on the obtained detection history, thepredetermined procedure of recognition for the target object upon itbeing determined that the target object is located in the attentionregion.

A second exemplary aspect of the present disclosure is a method appliedto an apparatus to be installed in an own vehicle equipped with anobject detection sensor that repeatedly performs a detection operationfor detecting objects around the own vehicle. The method recognizes,based on results of the detection operations, a target object inaccordance with a predetermined procedure, and perform at least one of acollision avoidance operation and a damage mitigation operation for theown vehicle with respect to the recognized target object. The methodincludes defining an attention region near a blocking obstacle upon theblocking object being determined to be located between the own vehicleand the target object based on the results of the detection operations,and determining whether the target object is located in the attentionregion. The method includes obtaining, upon it being determined that thetarget object is located in the attention region, a detection history ofthe target object by the object detection sensor before the targetobject is determined to be located in the attention region. The methodincludes adjusting, based on the obtained detection history, thepredetermined procedure of recognition for the target object upon itbeing determined that the target object is located in the attentionregion.

If there is a blocking obstacle located between the own vehicle and atarget object, and the blocking obstacle blocks the view from the ownvehicle, it may be difficult for the apparatus or method to recognizethe target object. For example, if the target object is located in theattention region defined near the blocking obstacle, it is desired toimmediately recognize the target object in view of reduction ofdeactivation of at least one safety device, and also to reliablyrecognize the target object in view of reduction of unnecessaryactivation of the at least one safety device.

In addition, urgency of recognition for the target object that islocated in the attention region is changed depending on the detectionhistory of the target object before the target object is located in theattention region.

From this viewpoint, each of the apparatus and method is adapted todetermine whether the target object is located in the attention region,and upon determining that the target object is located in the attentionregion, each of the apparatus and method is adapted to obtain thedetection history of the target object before determining that thetarget object is located in the attention region. Then, each of theapparatus and method is adapted to adjust the procedure for recognizingthe target object as a function of the obtained detection history.

Specifically, upon it being determined that the target object has notbeen captured before determining that the target object is located inthe attention region, the urgency of recognition for the target objectis high, so that it is necessary to cause the urgency of recognition forthe target object to have a higher priority than the reliability ofrecognition for the target object.

Otherwise, upon it being determined that the target object has beencaptured before determining that the target object is located in theattention region, the urgency of recognition for the target object isrelatively low, so that it is necessary to cause the reliability ofrecognition for the target object to have a higher priority than theurgency of recognition for the target object.

For this reason, the above configuration of each of the apparatus andmethod makes it possible to perform the object recognition task for thetarget object while factoring in the urgency of recognition for thetarget object. This enables the at least one safety device to besuitably activated to satisfy both the urgency and the reliability ofrecognition for the target object even if the target object is locatedin the attention region.

BRIEF DESCRIPTION OF THE DRAWINGS

Other aspects of the present disclosure will become apparent from thefollowing description of embodiments with reference to the accompanyingdrawings in which:

FIG. 1 is a block diagram schematically illustrating an example of thestructure of a pre-crash safety system according to an exemplaryembodiment of the present disclosure;

FIG. 2A is a view schematically illustrating an example of firstdetection information about a radar-based object according to theexemplary embodiment;

FIG. 2B is a view schematically illustrating an example of seconddetection information about an image-based object according to theexemplary embodiment;

FIG. 3 is a view schematically illustrating an example of a blockingobstacle, an attention region defined near the blocking obstacle, and apedestrian according to the exemplary embodiment;

FIG. 4 is a view schematically illustrating an example of the positionalrelationship between the attention region and a pedestrian;

FIG. 5 is a graph schematically illustrating an example of therelationship between a threshold number and the urgency of target-objectrecognition;

FIG. 6 is a flowchart schematically illustrating an example of acondition adjustment task carried out by an electronic control unit(ECU) illustrated in FIG. 1; and

FIG. 7 is a flowchart schematically illustrating first and secondmodifications of the exemplary embodiment.

DETAILED DESCRIPTION OF EMBODIMENT

The following describes an exemplary embodiment of the presentdisclosure with reference to the accompanying drawings.

FIG. 1 schematically illustrates a pre-crash safety (PCS) system 100based on a vehicle control apparatus according to the first embodimentinstalled in an own vehicle 50. The PCS system 100 is capable of

1. Recognizing an object located around the own vehicle 50, such asahead of the own vehicle 50 in the travelling direction of the ownvehicle 50, i.e. in the forward direction of the own vehicle 50

2. Performing control tasks of the own vehicle 50 including a collisionavoidance operation to avoid collision between the recognized object andthe own vehicle 50 and/or a damage mitigation operation to mitigatedamage due to collision therebetween

Referring to FIG. 1, the PCS system 100 includes an electronic controlunit (ECU) 10, a radar device 21, an imaging device 22, which are anexample of object detection sensors, a vehicle speed sensor 23, awarning device 31, a brake device 32, and a steering device 33. In FIG.1, the radar device 21 and the imaging device 22 constitute objectdetecting sensors, and at least the ECU 10 serves as a vehicle controlapparatus. The warning device 31, brake device 32, and steering device33 serve as safety devices.

The sensors 21 to 23 are connected to the ECU 10 and are operative toinput various pieces of detected information to the ECU 10.

For example, the radar device 21 is designed to detect objects locatedin front of the own vehicle 50 using, for example, directionalelectromagnetic waves, i.e. probe waves, such as millimeter waves orradar waves. The radar device 21 is mounted at, for example, the centerof the front end of the own vehicle 50 such that its optical axis of theprobe waves is directed toward the forward direction of the own vehicle50.

The radar device 21 has a predetermined detection range that has apredetermined view angle, such as a detection angle, or scanning angle,and extends in the right and left direction around the optical axis.That is, the radar device 21 is capable of detecting the position of anobject within the detection range.

Specifically, the radar device 21 performs, in a first period, an objectinformation obtaining task to

1. Transmit probe waves to the detection range through a transmittingantenna

2. Receive reflected waves, i.e. echoes, based on reflection of thetransmitted radar waves by the outer surface of an object throughrespective receiving antennas

3. Calculate the relative position of the object relative to the ownvehicle 50 based on the transmission time of the prove waves and thereception times of the respective reflected waves

4. Calculate the azimuth of the object based on the differences in phasebetween the reflection waves received by the respective receivingantennas

5. Calculate the relative speed between the own vehicle 50 and theobject based on the frequencies of the reflected waves; the frequencieshave been changed based on the Doppler effect.

That is, the radar device 21 obtains, in the first period, firstdetection information including the relative position, azimuth, and therelative speed of the object. Note that objects detected by the radardevice 21 will be referred to as radar-based objects.

As illustrated in FIG. 2A, each of the radar device 21 and the ECU 10has a coordinate system defined by an X axis and a Y axis; the X axisextends in the width direction, i.e. lateral direction, of the ownvehicle 50 while passing through the center, i.e. an origin, of thefront end of the own vehicle 50. The Y axis extends from the center ofthe front end of the own vehicle 50 in the travelling direction of theown vehicle 50.

The coordinates of the relative position of a radar-based object have alateral position in the X axis and a longitudinal position in the Yaxis.

That is, as illustrated in FIG. 2A, if a radar-based object is apreceding vehicle PV in front of the own vehicle 50, the radar device 21obtains the first detection information about the radar-based object PVincluding

1. The relative position (x1, y1) of, for example, the rear end of theradar-based object PV in the XY coordinate system

2. The azimuth θ of the relative position (x1, y1) of the radar-basedobject PV relative to the own vehicle 50 in the XY coordinate system

3. The relative speed between the own vehicle 50 and the radar-basedobject PV

The radar device 21 also outputs, to the ECU 10, the obtained firstdetection information about the radar-based object in the first period.

The imaging device 22 is designed as a camera device, such as a CCDcamera device, a CMOS image sensor device, or a near-infrared cameradevice. For example, the imaging device 22 is mounted to the center of apredetermined portion, such as the upper end of the front windshield, ofthe own vehicle 50 in the vehicle width direction at a predeterminedheight. The imaging device 22 has an optical axis extending in front ofthe own vehicle 50. The imaging device 22 has a region, i.e. an imagingrange, that horizontally extends around the optical axis within apredetermined angular range, i.e. a predetermined angle of view. Theimaging device 22 captures, from the predetermined height, i.e. from ahigher point of view, images of the region, i.e. the imaging range inthe second period, and sends, to the ECU 10, the captured images in thesecond period. Note that a monocular camera device or a stereo cameradevice can be used as the imaging device 22.

The vehicle speed sensor 23 is mounted to the rotary shaft of the ownvehicle 50, which transfers torque to the driving wheels of the ownvehicle 50, and is operative to obtain the speed of the own vehicle 50as vehicle speed V based on the number of turns of the driving wheels.

The warning device 31 includes a speaker and/or a display mounted in thecompartment of the own vehicle 50. The warning device 31 is configuredto output warnings including, for example, warning sounds and/or warningmessages to inform the driver of the presence of an object in responseto a control instruction sent from the ECU 10.

The brake device 32 is configured to brake the own vehicle 50. The brakedevice 32 is activated in response to a control instruction sent fromthe ECU 10 when the ECU 10 determines that there is a high possibilityof collision of the own vehicle 50 with an object. Specifically, thebrake device 32 performs a brake-assist function of increasing brakingforce, which is based on the driver's brake operation, to the ownvehicle 50, or an automatic brake function of automatically braking theown vehicle 50 if there is no braking operation by the driver.

The steering device 33 is configured to control the travelling course ofthe own vehicle 50. The steering device 33 is activated in response to acontrol instruction sent from the ECU 10 when the ECU 10 determines thatthere is a high possibility of collision of the own vehicle 50 with anobject. Specifically, the steering device 33 performs a steering assistfunction of assisting a driver's steering operation of the steeringwheel of the own vehicle 50, or an automatic steering function ofautomatically steering the own vehicle 50 if there is no steeringoperation by the driver.

The ECU 10 is designed as, for example, a microcomputer including a CPU10 a, a memory 10 b comprised of at least a ROM, a RAM, and/or asemiconductor memory such as a flash memory. The ECU 10 includes an I/Odevice (I/O) 10 c connected via input ports to the radar device 21, theimaging device 22, and the vehicle speed sensor 23 and connected viaoutput ports to the warning device 31, the brake device 32, and thesteering device 33. The various functions of the PCS system 100 areimplemented by the CPU 10 a in executing programs that are stored innon-transitory recording media. For example, the memory 10 b serves asthe non-transitory recording media in which the programs are stored.Furthermore, the CPU 10 a executes the programs, thus executing methodscorresponding to the programs. The PCS system 100 is not necessarilyconfigured with a single microcomputer, and it would be equally possibleto have a plurality of microcomputers.

In particular, the ECU 10 is configured to perform a PCS control taskthat

1. Recognizes at least one object in accordance with the first detectioninformation input from the radar device 21 and the second detectioninformation input from the imaging device 22

2. Controls at least one of the warning device 31, the brake device 32,and the steering device 33 for each of the recognized at least oneobject

The ECU 10 functionally includes, for example, an object recognizer 41,a collision possibility determiner 42 and an activation timingcontroller 43 for implementing the PCS control task.

The object recognizer 41 periodically obtains the first detectioninformation from the radar device 21, and periodically obtains thecaptured image from the imaging device 22, and stores each of thecaptured images in the memory 10 b.

The object recognizer 41 recognizes at least one radar-based object inaccordance with the first detection information.

The object recognizer 41 uses object model dictionary files DF that havebeen stored beforehand in the memory 10 b. The object model dictionaryfiles DF are provided for respective types of object, such as vehicles,pedestrians, bicycles, on-road obstacles, etc. In particular, each ofthe dictionary files DF includes object models, i.e. feature quantitytemplates, i.e. feature quantity patterns, provided for thecorresponding object type.

For example, the dictionary file DF for vehicles includes front-endfeature patterns for each of various vehicle models includinglarge-sized models, standard-sized models, and mini-sized models, andrear-end feature patterns for each of the various vehicle models.

In addition, the dictionary file DF for pedestrians includes, forexample, upper-body feature patterns, lower-body feature patterns, andwhole-body feature patterns.

The object recognizer 41 performs pattern matching of the captured imagestored in the memory 10 b with each of the feature patterns included inall the dictionary files DF to thereby detect at least one object andits type, such as a vehicle, a pedestrian, a cyclist, an on-roadobstacle, etc in the captured image as an image-based object.

In particular, the object recognizer 41 obtains second detectioninformation about the at least one image-based object as follows.

For example, as illustrated in FIG. 2B, if an image-based object is apreceding vehicle PV1 in front of the own vehicle 50, the objectrecognizer 41 obtains the second detection information about theimage-based object PV1 including

1. The left and light edge positions xL, xR of, for example, the rearend of the image-based object PV1 in the X axis of the XY coordinatesystem to thereby obtain the center position xC of, for example, therear end of the image-based object PV1 in the XY coordinate system

2. The lateral width WL of the image-based object PV1 in the XYcoordinate system

The object recognizer 41 obtains first position information about eachradar-based object based on the relative position of the correspondingradar-based object, and second position information about eachimage-based object based on the feature points corresponding to theimage-based object.

Then, the object recognizer 41 determines that a radar-based object andan image-based object are the same object when the corresponding firstposition information is close to the corresponding second positioninformation. Next, the object recognizer 41 matches the correspondingfirst detection information with the corresponding second detectioninformation, thus generating fusion information.

Specifically, if the second position information about an image-basedobject is located to be close to the first position information about aradar-based object, there is a high possibility of a correspondingactual object being located at the position based on the first positioninformation. The state where the first position information about eachradar-based object is identical to or close to the second positioninformation about the corresponding image-based object will be referredto as a fusion state, and an object detected in the fusion state will bereferred to as a fusion-based object. In other words, the fusion stateshows that the radar device 21 and the imaging device 22 have eachobtained the position of an object with high accuracy.

For example, the fusion information about a fusion-based object includes

1. The relative position of the fusion-based object relative to the ownvehicle 50 for example based on the first detection information

2. The azimuth of the relative position of the fusion-based objectrelative to the own vehicle 50 for example based on the first detectioninformation

3 The relative speed between the own vehicle 50 and the fusion-basedobject for example based on the first detection information

4. The lateral width of the fusion-based object for example based on thesecond detection information

The object recognizer 41 performs, in a predetermined recognitionperiod, an object recognizing task that includes

1. Obtaining the first detection information about each radar-basedobject

2. Obtaining the second detection information about each image-basedobject

3. Obtaining the fusion information about each fusion-based objectdetected in the fusion state

The object recognizer 41 recognizes that one or more actual objects arelocated around the own vehicle 50 based on the corresponding one or morefusion-based objects detected thereby during a predetermined number ofperiods.

Specifically, the object recognizer 41 recognizes that an actual objectis located at the relative position of a corresponding fusion-basedobject after having continuously recognized the same fusion-based objectat least a predetermined threshold number of times A. The thresholdnumber of times A is determined such that, if the same fusion-basedobject has continuously been recognized at least the threshold number oftimes A, it is determined that an actual object corresponding to thefusion-based object is likely to be located at the relative position ofthe fusion-based object. The threshold number of times A in a normalrecognition mode is set to, for example, three times.

That is, the threshold number of times A serves as a recognitioncondition according to the exemplary embodiment.

The object recognizer 41 stores, for each recognition period, the firstdetection information about each radar-based object, the seconddetection information about each image-based object, and the fusioninformation about each fusion-based object into the memory 10 b as adetection history file DHF.

In particular, the object recognizer 41 stores, as the detection historyfile DHF, a cumulative detection number N, whose initial value is set tozero, prepared for an object detected as any one of the radar-basedobject, the image-based object, and the fusion-based object.

That is, the object recognizer 41 increments the cumulative detectionnumber N prepared for an object by 1 each time the same object isdetected as any one of the radar-based object, the image-based object,and the fusion-based object. That is, the object recognizer 41increments the cumulative detection number N prepared for an object by 1from the initial value of zero upon the object is detected for the firsttime as any one of the radar-based object, the image-based object, andthe fusion-based object.

The collision possibility determiner 42 has a predetermined collisionprediction region PR previously defined for the own vehicle 50 in the XYcoordinate system. The collision prediction region PR serves as acriterion in performing a collision avoidance task.

For example, the collision prediction region PR

1. Has the center axis corresponding to the Y axis illustrated in FIG.2A

2. Has a rightward width based on a rightward limit XR in the rightwarddirection relative to the travelling direction

3. Has a leftward width based on a leftward limit XL in the rightwarddirection relative to the travelling direction

5. Has a predetermined length, i.e. depth, L from the center of thefront end of the own vehicle 50 along the Y axis direction

Upon recognizing an object, such as a fusion-based object, the collisionpossibility determiner 43 determines whether there is a possibility ofcollision of the own vehicle 50 with the fusion-based object using thecollision prediction region PR.

Specifically, the collision possibility determiner 42 determines whetherthe lateral position of the recognized fusion-based object is locatedwithin the collision prediction region PR, and determines that there isa possibility of collision of the own vehicle 50 with the recognizedfusion-based object upon determining that the lateral position of therecognized fusion-based object is located within the collisionprediction region PR.

The activation timing controller 43 calculates a time to collision(ITC), which represents a margin time until which the own vehicle 50would collide with the recognized fusion-based object in accordance withthe relative position of the recognized fusion-based object and therelative speed between the own vehicle 50 and the recognizedfusion-based object upon determining that there is a possibility ofcollision of the own vehicle 50 with the recognized fusion-based object.

Then, the activation timing controller 43 compares the calculated TTCwith the activation timings of the respective safety devices, i.e. thethresholds representing the respective activation timings.

Specifically, the thresholds are respectively set for the warning device31, the brake device 32, and the steering device 33. The relative sizesamong the thresholds are identical to the above relative sizes among theactivation timings.

The thresholds respectively set for the warning device 31, the brakedevice 32, and the steering device 33 are for example determined suchthat the threshold for the warning device 31 is larger than thethreshold for the brake device 32, and the threshold for the steeringdevice 33 is larger than the threshold for the brake device 32.

If the own vehicle 50 approaches the recognized fusion-based object, sothat the TTC becomes lower than the threshold for the activation timingfor the warning device 31, the activation timing controller 43determines that it is time to activate the warning device 31, thustransmitting an activation control signal to the warning device 31. Thiscauses the warning device 31 to be activated to output warnings, thusinforming the driver of a risk of collision with the fusion-basedobject.

After activation of the warning device 31, if the own vehicle 50 furtherapproaches the fusion-based object with the brake pedal being notdepressed by the driver, so that the ITC further decreases to becomelower than the threshold for the activation timing for the automaticbrake function of the brake device 32, the activation timing controller43 determines that it is time to activate the automatic brake functionof the brake device 32, thus transmitting an activation control signalto the automatic brake function of the brake device 32. This causes thebrake device 32 to be activated to perform braking control of the ownvehicle 50.

On the other hand, after activation of the warning device 31, if the ownvehicle 50 further approaches the fusion-based object despite thedriver's depression of the brake pedal, so that the ITC furtherdecreases to become lower than the threshold for the activation timingfor the brake-assist function of the brake device 32, the activationtiming controller 43 determines that it is time to activate thebrake-assist function of the brake device 32, thus transmitting anactivation control signal to the brake-assist function of the brakedevice 32. This causes the brake device 32 to be activated to increasebraking force based on the driver's depression of the braking pedal.

After activation of the brake device 32, if the own vehicle 50 furtherapproaches the fusion-based object, so that the TTC further decreases tobecome lower than the threshold for the activation timing for thesteering device 33, the activation timing controller 43 determines thatit is time to activate the steering device 33, thus transmitting anactivation control signal to the steering device 33. This causes thesteering device 33 to be activated to perform forcible steering controlof the own vehicle 50.

Note that the activation timing controller 43 can be configured to

1. Compare the actual relative distance calculated based on the TTC withpredetermined thresholds for the activation timings of the respectivesafety devices

2. Determine whether to activate each of the safety devices inaccordance with the results of the comparison.

The above PCS control task implemented by the functional modules 41 to43 aims to mitigate or avoid collision damage between the own vehicle 50and a recognized object, such as the fusion-based object.

If there is a blocking obstacle located between the own vehicle 50 andan object, and the blocking obstacle blocks the view from the ownvehicle 50 toward the object, it may be difficult for the PCS system 100to recognize the object.

FIG. 3A illustrates a situation where there is a stopped vehicle 60 as ablocking obstacle between the own vehicle 50 and a pedestrian 70 as anobject to be recognized. That is, in this situation, the PCS system 100installed in the own vehicle 50 aims to recognize the pedestrian 70, andperforms the PCS control task for the recognized pedestrian 70.

The ECU 10 of the PCS system 100 according to the exemplary embodimentis configured to, if the stopped vehicle 60 is recognized by the radardevice 21 and the imaging device 22, define an attention region S (seeFIG. 3) near the stopped vehicle 60 in the XY coordinate system; theattention region S includes a hidden region that is hidden by thestopped vehicle 60 with respect to the own vehicle 50.

For example, as illustrated in FIG. 3, the attention region S, which hasa predetermined shape, includes a first region S1 and a second region S2in the XY coordinate system. The first region S1 is blocked by thestopped vehicle 60 when viewed from the own vehicle 50, that is, islocated ahead of the stopped vehicle 60 when viewed from the own vehicle50. The second region S2 is located to be adjacent to the closer side ofthe stopped vehicle 60 to the own vehicle 50.

Let us consider a situation where the pedestrian 70 lies in theattention region S and suddenly runs in front of the own vehicle 50. Inthis situation, it is desired to activate the safety devices 31 to 33earlier.

From this viewpoint, the conventional vehicle control apparatus setforth above relaxes a level of a predetermined object recognitioncondition for the attention region S upon the stopped vehicle 60 beingdetected to be lower than the level of the predetermined objectrecognition condition for the same region S upon no blocking obstaclesbeing detected. For example, the conventional vehicle control apparatussets the threshold number of times A for the attention region S upon thestopped vehicle 60 being detected to be lower than the threshold numberof times A for the same region S upon no blocking obstacles beingdetected.

This enables the vehicle control apparatus to recognize the pedestrian70 located in the attention region S faster, making it possible toactivate the safety devices earlier even if the pedestrian 70 suddenlyruns in front of the own vehicle 50.

The conventional vehicle control apparatus relaxes the level of thepredetermined object recognition condition for the attention region Swithout exception. This may result in a target object located in theattention region S, for which faster recognition is not necessarilyrequired, being recognized faster. This may result in unnecessaryactivation of the safety devices 31 to 33.

For example, FIG. 4 schematically illustrates a case where a pedestrian70, who is located ahead in the travelling direction of the own vehicle50 is moving toward the attention region S; the pedestrian 70 has beencontinuously recognized by the object detection sensors 21 and 22. Inthis case, even if the pedestrian 70 has entered the attention region S,it is possible for the PCS system 100 to predict an accurate movementtrajectory of the pedestrian 70, because the pedestrian 70 has beenalready detected by the PCS system 100. For this reason, in this case,it is unnecessary to recognize the pedestrian 70 faster. In other words,unnecessary faster recognition of the pedestrian 70, which has beenalready detected by the object detection devices 21 and 22, may resultin unnecessary activation of the safety devices 31 to 33.

From this viewpoint, the ECU 10 of the PCS system 100 according to theexemplary embodiment is configured to

1. Determine whether a target object is located in the attention regionS defined around a blocking obstacle

2. Obtain, upon determining that the target object is located in theattention region S, the past detection situation, i.e. the detectionhistory, of the target object

3. Adjust a procedure for recognizing the target object as a function ofthe obtained detection history

Specifically, the ECU 10 of the PCS system 100 is configured to

(1) Relax the recognition condition for the target object upondetermining that the target object has not been captured beforedetermination that the target object is located in the attention regionS

(2) Maintain the recognition condition for the target object unchangedupon determining that the target object has been captured beforedetermination that the target object is located in the attention regionS

That is, the ECU 10 is configured to

(1) Perform the object recognition task in a condition relaxation modeusing a relaxed recognition condition, such as a threshold number B oftimes lower than the threshold number of times A upon determining thatthe target object has not been captured before determination that thetarget object is located in the attention region S

(2) Perform the object recognition task in the normal recognition modeusing the recognition condition, such as the threshold number of times A

Specifically, the conventional vehicle control apparatus makesrecognition of a target object faster without exception upon determiningthat the target object is located in the attention region S whileimmediate recognition has a higher priority than reliable recognition.

In contrast, the ECU 10 according to the exemplary embodiment isspecifically configured to perform a recognition condition adjustmenttask that

(1) Determines whether it is necessary to immediately recognize a targetobject

(2) Makes recognition of the target object faster upon determining thatit is necessary to immediately recognize the target object

(3) Disables immediate recognition of the target object upon determiningthat it is unnecessary to immediately recognize the target object

The ECU 10 according to the exemplary embodiment functionally includesan attention region defining unit 45, a target object determiner 46, adetection history obtainer 47, a recognition condition determiner 48,and a threshold setter 49 that implement the specific configuration,i.e. the recognition condition adjustment task.

The attention region defining unit 45 is configured to define anattention region S when the object recognizer 41 detects a blockingobstacle 60, for example, a stopped vehicle 60 in the exemplaryembodiment, in accordance with the first detection informationperiodically obtained from the radar device 21 and the second detectioninformation periodically obtained from the imaging device 22.

Specifically, as illustrated in FIG. 4, if there is a stopped vehiclelocated ahead in the travelling direction of the own vehicle 50 istravelling, the object recognizer 41 detects a preceding vehicle basedon the result of the pattern matching of the captured image stored inthe memory 10 b with the rear-end feature patterns Q included in thedictionary files DF. Note that the object recognizer 41 can recognizethe preceding vehicle based on the result of the pattern matching of thecaptured image stored in the memory 10 b with the front-end featurepatterns included in the dictionary files DF.

Additionally, the radar device 21 detects plural detection points P,i.e. radar reflection points P, of the preceding vehicle located inparallel to the travelling direction of the own vehicle 50 while thelocation of the set of the plural detection points P is unchanged. Atthat time, the object recognizer 41 detects a closer side of thepreceding vehicle ahead in the travelling direction of the own vehicle50 in accordance with the first detection information based on theplural detection points P.

This enables the attention region defining unit 45 to detect thepreceding vehicle 60 as a stopped vehicle 60 ahead in the travellingdirection of the own vehicle 50. Note that the object recognizer 41 candetect the stopped vehicle 60 based on the relative speed between theown vehicle 50 and the stopped vehicle 60.

Then, the attention region defining unit 45 define the attention regionS (see FIG. 3) around the stopped vehicle 60 in the XY coordinatesystem. As described above, the attention region S includes the firstregion S1 and the second region S2 in the XY coordinate system. Thefirst region S1 is blocked by the stopped vehicle 60 when viewed fromthe own vehicle 50, that is, is located ahead of the stopped vehicle 60when viewed from the own vehicle 50. The second region S2 is located tobe adjacent to the closer side, i.e. the left side, of the stoppedvehicle 60 to the own vehicle 50.

That is, the attention region S includes the first region S1 blocked bythe stopped vehicle 60 when viewed from the own vehicle 50, that is, thefirst region S1 that it is difficult for the own vehicle 50 to recognizeobjects in.

Upon the attention region defining unit 45 defining the attention regionS, the target object determiner 46 determines whether a target object islocated in the attention region S. Specifically, upon determining that afusion-based object is detected in the attention region S, the targetobject determiner 46 determines that the target object is located in theattention region S. In particular, the ECU 10 according to the exemplaryembodiment is designed to assume recognition of a pedestrian 70 or abicycle suddenly running from the attention region S in front of the ownvehicle 50. For this reason, the target obtainer 46 can be configured toidentify the type of the target object located in the attention region Sin accordance with the result of the pattern matching described above,and determine that a pedestrian 70 is located in the attention region Sas the target object.

For example, if a pedestrian 70 is located in the first region S1 of theattention region S, because the first region S1 is blocked by thestopped vehicle 60, the ECU 10 for example detects the pedestrian 70 inaccordance with the first detection information obtained by the radardevice 21 and the result of the pattern matching of the captured imagewith the upper-body feature patterns included in the dictionary file DF.This is because the lower-body of the pedestrian 70 is likely to beblocked by the stopped vehicle 60.

Upon determining that the target object is located in the attentionregion S, the detection history obtainer 47 obtains the detectionhistory for the target object stored in the memory 10 b before thedetermination that the target object is located in the attention regionS. The recognition condition determiner 48 determines whether immediaterecognition is required in accordance with the obtained detectionhistory.

Specifically, the object recognizer 41 obtains, from the detectionhistory file DHF, the cumulative detection number N prepared for thetarget object before the determination that the target object is locatedin the attention region S. As described above, the cumulative detectionnumber N prepared for the target object is incremented by 1 each timethe same target object is detected as any one of the radar-based object,the image-based object, and the fusion-based object. That is, if thetarget object is detected to be located in the attention region S forthe first time, the cumulative detection number N prepared for thetarget object before the determination that the target object is locatedin the attention region S remains to be the initial value of zero.

After reading out the cumulative detection number N prepared for thetarget object from the detection history file DHF, the recognitioncondition determiner 48 determines whether the cumulative detectionnumber N is less than a predetermined threshold number Th.

Upon determining that the cumulative detection number N is less than thepredetermined threshold number Th, the recognition condition determiner48 determines that the target object has not been captured before thedetermination that the target object is located in the attention regionS. Then, the recognition condition determiner 48 relaxes the recognitioncondition for the attention region S in the condition relaxation mode tobe lower than the recognition condition for the attention region S inthe normal recognition mode.

Specifically, the recognition condition determiner 48 changes thethreshold number of times A, i.e. three times, in the normal recognitionmode to one time in the condition relaxation mode. That is, because thecumulative detection number N is lower than the threshold number N, thetarget object is estimated to suddenly appear in the attention region S,so that the recognition condition determiner 48 determines that theurgency of recognition for the target object is high.

In contrast, upon determining that the cumulative detection number N isequal to or more than the threshold number Th, the recognition conditiondeterminer 48 determines that the target object has been alreadydetected before the determination that the target object is located inthe attention region S. Then, the recognition condition determiner 48maintains the recognition condition for the attention region Sunchanged, in other words, maintains the normal recognition modeunchanged.

Specifically, because the cumulative detection number N is equal to orhigher than the threshold number N, the target object, such as thepedestrian 70 illustrated in FIG. 4, is estimated to have been alreadydetected before entering the attention region S, so that the recognitioncondition determiner 48 determines that urgency of recognition for thetarget object is relatively low.

As described above, the ECU 10 according to the exemplary embodimentuses, as the requirement of changing the recognition condition for theattention region S, the cumulative detection number N prepared for atarget object being less than the threshold number Th. In particular,the ECU 10 according to the exemplary embodiment uses the thresholdnumber Th as a determination criterion to determine whether the targetobject has been captured before determination that the target object islocated in the attention region S.

For example, the threshold setter 49 of the ECU 10 according to theexemplary embodiment variably sets the threshold number Th in accordancewith the vehicle speed V of the own vehicle 50 measured by the vehiclespeed sensor 23, the relative position of the target object relative tothe own vehicle 50, and the relative position of the stopped vehicle 60relative to the own vehicle 50.

FIG. 5 illustrates an example of the relationship between the thresholdnumber Th and that urgency of recognition for the target object detectedin the attention region S. FIG. 5 shows that the threshold number Thdepends on the urgency of recognition for the target object detected inthe attention region S. Specifically, the higher the threshold number This, the more the requirement of relaxing the recognition condition forthe attention region S is likely to be satisfied, so that the thresholdnumber Th is set to be higher as the urgency of recognition for thetarget object detected in the attention region S is higher. On the otherhand, the lower the threshold number Th is, the less the requirement ofrelaxing the recognition condition for the attention region S is likelyto be satisfied, so that the threshold number Th is set to be lower asthe urgency of recognition for the target object detected in theattention region S is lower.

That is, the threshold setter 49 is configured to set a value of thethreshold number Th in accordance with the vehicle speed V of the ownvehicle 50 measured by the vehicle speed sensor 23, the relativeposition of the target object relative to the own vehicle 50, and therelative position of the stopped vehicle 60 relative to the own vehicle50.

For example, the threshold setter 49 sets the threshold number Th to behigher as the relative distance between the own vehicle 50 and thestopped vehicle 60 or the target object becomes smaller, because thecloser the stopped vehicle 60 or the target object is to the own vehicle50, the higher the urgency of recognition for the target object becomes.In contrast, the threshold setter 49 sets the threshold number Th to belower as the relative distance between the own vehicle 50 and thestopped vehicle 60 or the target object becomes larger, because thefarther the stopped vehicle 60 or the target object is to the ownvehicle 50, the lower the urgency of recognition for the target objectbecomes.

Similarly, the threshold setter 49 sets the threshold number Th to behigher as the vehicle speed V of the own vehicle 50 becomes higher,because the higher the vehicle speed V of the own vehicle 50 is, thehigher the urgency of recognition for the target object becomes. Incontrast, threshold setter 49 sets the threshold number Th to be loweras the vehicle speed V of the own vehicle 50 becomes lower, because thelower the vehicle speed V of the own vehicle 50 is, the lower theurgency of recognition for the target object becomes.

The threshold setter 49 can variably set the threshold number Th inaccordance with at least one of the vehicle speed V of the own vehicle50 measured by the vehicle speed sensor 23, the relative position of thetarget object relative to the own vehicle 50, and the relative positionof the stopped vehicle 60 relative to the own vehicle 50. The thresholdsetter 49 can also variably set the threshold number Th in accordancewith the compatible conditions determined based on the vehicle speed Vof the own vehicle 50 measured by the vehicle speed sensor 23, therelative position of the target object relative to the own vehicle 50,and the relative position of the stopped vehicle 60 relative to the ownvehicle 50.

The following describes the recognition condition adjustment taskcarried out by the ECU 50 in a predetermined condition adjustmentperiod. As described above, the ECU 50 performs the object recognitiontask in the recognition period. That is, the ECU 50 is configured toperform the object recognition task for each recognition period usingthe object recognition condition determined at the correspondingrecognition period. The recognition period and the condition adjustmentperiod can be set to be identical to or different from each other.

Upon executing the condition adjustment task, the ECU 10 serves as, forexample, the attention region defining unit 45, to determine whetherthere is a stopped vehicle 60 as a blocking obstacle located ahead inthe travelling direction of the own vehicle 50 in the combination ofsteps S11 and S12 of FIG. 6.

Specifically, the ECU 50 determines whether one of the rear-end featurepatterns Q included in the dictionary files DF is detected in thecaptured image based on the result of pattern matching of the rear-endfeature patterns with the captured image in step S11.

Upon determining that one of the rear-end feature patterns Q is detectedin the captured image (YES in step S11), the ECU 50 determines that apreceding vehicle is located ahead in the travelling direction of theown vehicle 50. Then, the ECU 50 determines whether a closer side of thepreceding vehicle detected in step S11 has been detected while thelocation of the side is unchanged in step S12.

Specifically, upon obtaining plural detection points P, i.e. radarreflection points P, of the preceding vehicle located in parallel to thetravelling direction of the own vehicle 50 while the location of the setof the plural detection points P is unchanged (YES in step S12), the ECU50 determines that the closer side of the preceding vehicle has beendetected while the location of the preceding vehicle is unchanged. Thisresults in the ECU 50 determining that the stopped vehicle 60 beinglocated ahead in the travelling direction of the own vehicle 50. In stepS12, the ECU 10 can detect the stopped vehicle 60 based on the relativespeed between the own vehicle 50 and the stopped vehicle 60. Then, therecognition condition adjustment task proceeds to step S12A.

Otherwise, upon determining that at least one of the determination instep S11 and the determination in step S12 is negative (NO in step S11or in step S12), the ECU 10 determines that there are no stoppedvehicles 60, i.e. no blocking obstacles, located ahead in the travellingdirection of the own vehicle 50. Then, the recognition conditionadjustment task proceeds to step S18.

In step S18, the ECU 10 serves as, for example, the recognitioncondition determiner 48, to maintain the recognition conditionunchanged, i.e. maintains the recognition condition in the normalrecognition mode.

In step S12A, the ECU 10 serves as, for example, attention regiondefining unit 45, to define the attention region S (see FIG. 3) aroundthe stopped vehicle 60 in the XY coordinate system.

Next, in step S13, the ECU 10 serves as, for example, the target objectdeterminer 46, to determine whether a pedestrian 70 for example selectedas a target object is located in the attention region S. Specifically,the ECU 10 determines whether a pedestrian 70, which is a fusion-basedobject, is located in the attention region S in step S13. Upondetermining that a pedestrian 70 is located in the attention region S(YES in step S13), the recognition condition adjustment task proceeds tostep S14. Otherwise, upon determining that no pedestrians are located inthe attention region S (NO in step S13), the recognition conditionadjustment task proceeds to step S18. In step S18, the ECU 10 serves as,for example, recognition condition determiner 48, to maintain therecognition condition unchanged, i.e. maintains the recognitioncondition in the normal recognition mode.

In step S14, the ECU 10 serves as, for example, the threshold setter 49,to set a value of the threshold number Th in accordance with the vehiclespeed V of the own vehicle 50 measured by the vehicle speed sensor 23,the relative position of the target object relative to the own vehicle50, and the relative position of the stopped vehicle 60 relative to theown vehicle 50.

Next, in step S15, the ECU 10 serves as, for example, the detectionhistory obtainer 47, to obtain the detection history for the pedestrian70, who has been detected in step S13, stored in the memory 10 b beforethe determination that the target object is located in the attentionregion S. Specifically, in step S15, the ECU 10 obtains, from thedetection history file DHF, the cumulative detection number N preparedfor the pedestrian 70 before the determination that the pedestrian 70 islocated in the attention region S.

Next, in step S16, the ECU 10 serves as, for example, the recognitioncondition determiner 48, to determine whether the cumulative detectionnumber N prepared for the pedestrian 70 is less than the thresholdnumber Th set in step S14.

Upon determining that the cumulative detection number N prepared for thepedestrian 70 is less than the threshold number Th (YES in step S16),the recognition condition adjustment task proceeds to step S17.Otherwise, upon determining that the cumulative detection number Nprepared for the pedestrian 70 is equal to or more than the thresholdnumber Th (NO in step S16), the recognition condition adjustment taskproceeds to step S18. In step S18, the ECU 10 serves as, for example,recognition condition determiner 48, to maintain the recognitioncondition unchanged, i.e. maintains the recognition condition in thenormal recognition mode.

In step S17, the ECU 10 serves as, for example, the recognitioncondition determiner 48, to change the recognition condition for theattention area S to be more relaxed in the condition relaxation modethan the recognition condition in the normal recognition mode.Specifically, in step S17, the ECU 10 changes the threshold number timesof A in the normal recognition mode to a lower value as the value of thethreshold number of times A in the recognition relaxation mode.

After the operation in step S17 or S18, the ECU 10 terminates thecondition adjustment task.

As described in detail above, the exemplary embodiment obtains thefollowing advantageous effects.

If there is a blocking obstacle located between the own vehicle 50 andan object, and the blocking obstacle blocks the view from the ownvehicle 50, it may be difficult for the ECU 10 to recognize the object.For example, let us assume a situation where there is a stopped vehicle60 as a blocking obstacle between the own vehicle 50 and a pedestrian 70as an object to be recognized. That is, in this situation, it isdesirable for the PCS system 100 to activate the safety devices 31 to 33depending on the urgency of recognition for the pedestrian 70.

From this viewpoint, the ECU 10 of the PCS system 100 according to theexemplary embodiment is configured to determine whether the pedestrian70 is located in the attention region S defined around the stoppedvehicle 60. Upon determining that the pedestrian 70 is located in theattention region S, the ECU 10 is configured to obtain the detectionhistory of the pedestrian 70 before determining that the pedestrian 70is located in the attention region S. Then, the ECU 10 is configured toadjust the procedure for recognizing the pedestrian 70 as a function ofthe obtained detection history.

Specifically, the ECU 10 determines, based on the detection history ofthe pedestrian 70, whether the pedestrian 70 has been captured beforedetermining that the pedestrian 70 is located in the attention region S.

Upon determining that the pedestrian 70 has not been captured beforedetermining that the pedestrian 70 is located in the attention region S,the urgency of recognition for the pedestrian 70 is high, so that it isnecessary to cause the urgency of recognition for the pedestrian 70 tohave a higher priority than the reliability of recognition for thepedestrian 70.

Otherwise, upon determining that the pedestrian 70 has been capturedbefore determining that the pedestrian 70 is located in the attentionregion S, the urgency of recognition for the pedestrian 70 is relativelylow, so that it is necessary to cause the reliability of recognition forthe pedestrian 70 to have a higher priority than the urgency ofrecognition for the pedestrian 70.

For this reason, the above configuration of the PCS system 100 makes itpossible to perform the object recognition task for the pedestrian 70while factoring in the urgency of recognition for the pedestrian 70.This enables the safety devices 31 to 33 to be suitably activated tosatisfy both the urgency and the reliability of recognition for thepedestrian 70 even if the pedestrian 70 is located in the attentionregion S.

Specifically, the ECU 10 determines, based on the detection history ofthe pedestrian 70, whether the pedestrian 70 has been captured beforedetermining that the pedestrian 70 is located in the attention region S.

Upon determining that the pedestrian 70 has not been captured beforedetermining that the pedestrian 70 is located in the attention region S,the ECU 10 is configured to change a level of the recognition conditionin the normal recognition mode such that the changed level of therecognition condition in the condition relaxation mode is lower than thelevel of the recognition condition in the normal recognition mode.Otherwise, upon determining that the pedestrian 70 has been capturedbefore determining that the pedestrian 70 is located in the attentionregion S, the ECU 10 is configured to maintain the recognition conditionin the normal recognition mode unchanged.

That is, when it is determined that the pedestrian 70 has not beencaptured before determining that the pedestrian 70 is located in theattention region S, the target object is estimated to suddenly appear inthe attention region S, so that the recognition condition determiner 48determines that the urgency of recognition for the target object ishigh. In this case, the ECU 10 changes the level of the recognitioncondition in the normal recognition mode such that the changed level ofthe recognition condition in the condition relaxation mode is lower thenthe level of the recognition condition in the normal recognition mode,thus enabling the urgency of recognition for the pedestrian 70 to have ahigher priority than the reliability of recognition for the pedestrian70.

In contrast, when it is determined that the pedestrian 70 has beencaptured before determining that the pedestrian 70 is located in theattention region S, because the pedestrian 70 has been already detectedbefore the determination that the target object is located in theattention region S, the urgency of recognition for the pedestrian 70 isrelatively low. For this reason, the ECU 10 maintains the recognitioncondition in the normal recognition mode unchanged, thus enabling thereliability of recognition for the pedestrian 70 to have a higherpriority than the urgency of recognition for the pedestrian 70.

That is, the above configured ECU 10 enables the object recognition taskfor the pedestrian 70 to be performed while factoring in the urgency ofrecognition for the pedestrian 70.

In particular, as determination of whether the pedestrian 70 has beencaptured before determining that the pedestrian 70 is located in theattention region S, the ECU 10 is configured to determine whether thecumulative detection number N for the pedestrian 70 before determiningthat the pedestrian 70 is located in the attention region S is lower thethreshold number Th.

Upon determining that the cumulative detection number N for thepedestrian 70 before determining that the pedestrian 70 is located inthe attention region S is lower than the threshold number Th, the ECU 10is configured to determine that the pedestrian 70 has not been capturedbefore determining that the pedestrian 70 is located in the attentionregion S. Otherwise, upon determining that the cumulative detectionnumber N for the pedestrian 70 before determining that the pedestrian 70is located in the attention region S is equal to or higher than thethreshold number Th, the ECU 10 is configured to determine that thepedestrian 70 has been captured before determining that the pedestrian70 is located in the attention region S.

This configuration of the ECU 10 enables the detection history of thepedestrian 70 before determining that the pedestrian 70 is located inthe attention region S to be obtained with higher accuracy.

Change of the threshold number Th enables the urgency of recognition forthe pedestrian 70 to be changed; the urgency of recognition for thepedestrian 70 changes depending on the vehicle speed V of the ownvehicle 50, the relative position of the target object relative to theown vehicle 50, and the relative position of the stopped vehicle 60relative to the own vehicle 50.

From this viewpoint, the ECU 10 is configured to set the thresholdnumber Th in accordance with the vehicle speed V of the own vehicle 50measured by the vehicle speed sensor 23, the relative position of thetarget object relative to the own vehicle 50, and the relative positionof the stopped vehicle 60 relative to the own vehicle 50. Thisconfiguration enables a value of the threshold number Th to bedetermined to be suitable for the current degree of urgency ofrecognition for the pedestrian 70, thus making it possible to activatethe safety devices 31 to 33 to be suitable for the current degree ofurgency of recognition for the pedestrian 70.

Modifications

Upon determining that the pedestrian 70 is located in the attentionregion S, the ECU 10 according to the exemplary embodiment is configuredto obtain, from the memory 10 b, the cumulative detection number N forthe pedestrian 70 before determining that the pedestrian 70 is locatedin the attention region S. The present disclosure is however not limitedto this configuration.

Specifically, in step S15A of FIG. 7 according to a first modificationof the exemplary embodiment, the ECU 10 can be configured to obtain, asthe detection history of the pedestrian 70, a last relative movementdirection of the pedestrian 70 relative to the own vehicle 50 beforedetermining that the pedestrian 70 is located in the attention region S.For example, in step S15A, the ECU 10 can extract, among captured pluralframe images including a currently captured frame image, predeterminedfeature points in the pedestrian 70. Then, in step S15A, the ECU 10 canobtain optical flow vectors of the extracted feature points; each of theoptical flow vectors of a feature point represents an apparent movementof the feature point among the plural frame images. In step S15A, theECU 10 can obtain, based on the optical flow vectors, the inclination ofthe last movement direction of the pedestrian 70 to the travellingdirection of the own vehicle 50 as the last relative movement directionof the pedestrian 70 relative to the own vehicle 50.

Following the operation in step S15A, the ECU 10 can determine whetherthe obtaining of the last relative movement direction of the pedestrian70 relative to the own vehicle 50 has been successfully completed instep S16A.

Upon determining that the obtaining of the last relative movementdirection of the pedestrian 70 relative to the own vehicle 50 has notbeen successfully completed (NO in step S16A), the ECU 10 can determinethat the pedestrian 70 has not been captured before determining that thepedestrian 70 is located in the attention region S. That is, the ECU 10can determine that urgency of recognition for the pedestrian 70 is high,changing the recognition condition in the normal recognition mode to bemore relaxed (see step S17).

Otherwise, upon determining that the obtaining of the last relativemovement direction of the pedestrian 70 relative to the own vehicle 50has been successfully completed (YES in step S16A), the ECU 10 candetermine that the pedestrian 70 has been captured before determiningthat the pedestrian 70 is located in the attention region S. That is,the ECU 10 can determine that urgency of recognition for the pedestrian70 is relatively low, maintaining the recognition condition in thenormal recognition mode unchanged (see step S18).

In particular, upon determining that the obtaining of the last relativemovement direction of the pedestrian 70 relative to the own vehicle 50has been successfully completed (YES in step S16A), the ECU 10 can beconfigured to determine whether urgency of recognition for thepedestrian 70 is required in accordance with the last relative movementdirection of the pedestrian 70 relative to the own vehicle 50 accordingto a second modification of the exemplary embodiment.

Specifically, the ECU 10 according to the second modification can beconfigured to further determine whether the last relative movementdirection of the pedestrian 70 relative to the own vehicle 50 hascrossed the travelling direction of the own vehicle 50 in step S16B.

Upon determining that the last relative movement direction of thepedestrian 70 relative to the own vehicle 50 has substantially crossedthe travelling direction of the own vehicle 50 (YES in step S16B), theECU 10 can be configured to determine that urgency of recognition forthe pedestrian 70 is relatively low, maintaining the recognitioncondition in the normal recognition mode unchanged (see step S18).

Otherwise, upon determining that the last relative movement direction ofthe pedestrian 70 relative to the own vehicle 50 has been substantiallyparallel to the travelling direction of the own vehicle 50 (NO in stepS16B), the ECU 10 can be configured to determine that urgency ofrecognition for the pedestrian 70 is high, changing the recognitioncondition in the normal recognition mode to be more relaxed (see stepS17).

This configuration according to the second modification enables urgencyof recognition for the pedestrian 70 to be determined in accordance withboth

1. Whether the pedestrian 70 has been captured before it is determinedthat the pedestrian 70 is located in the attention region S

2. Whether the last relative movement direction of the pedestrian 70relative to the own vehicle 50 was across the travelling direction ofthe own vehicle 50

This enables more reliable collision mitigation and/or avoidanceoperation to be carried out for the pedestrian 70.

The ECU 10 according to the exemplary embodiment is configured to changethe threshold number of times A in the normal recognition mode to alower value as the value of the threshold number of times A in therecognition relaxation mode, thus relaxing the recognition condition forthe attention region S, but the present disclosure is not limited tothis configuration.

For example, the ECU 10 can be configured to

1. Receive the relative positions of plural fusion-based objects foreach of the recognition periods

2. Increment a same-object count value whose initial value is zero eachtime the relative position of a first fusion-based object in the pluralfusion-based object and the relative position of a second fusion-basedobject in the plural fusion-based object satisfy a predeterminedcondition in one of the recognition periods

3. Determine that the first fusion-based object and the secondfusion-based object are the same fusion-based object upon thesame-object count value having reached the threshold number of times A

4. Relax the predetermined condition upon determining that the targetobject has not been captured before determination that the target objectis located in the attention region S

This modification can be used for the radar-based objects or image-basedobjects in place of the fusion-based objects.

The ECU 10 is configured to detect a stopped vehicle 60 as an example ofa blocking obstacle located ahead in front of the own vehicle 50, butcan be configured to detect an on-road obstacle, such as a power ortelephone pole or a guardrail. In this modification, the ECU 10 can beconfigured to detect an on-road obstacle based on the result of thepattern matching of the captured image stored in the memory 10 b withthe feature patterns of the on-road obstacles included in the dictionaryfiles DF. Then, the ECU 10 can be configured to define an attentionregion S around the detected on-road obstacle.

The ECU 10 is configured to determine whether a pedestrian 70 is locatedin the attention region S as a target object to be recognized, but canbe configured to determine whether another type of target object to berecognized is located in the attention region S, such as a bicycle.

While the illustrative embodiment and its modifications of the presentdisclosure have been described herein, the present disclosure is notlimited to the embodiments and their modifications described herein.Specifically, the present disclosure includes any and all embodimentshaving modifications, omissions, combinations (e.g., of aspects acrossvarious embodiments), adaptations and/or alternations as would beappreciated by those in the art based on the present disclosure. Thelimitations in the claims are to be interpreted broadly based on thelanguage employed in the claims and not limited to examples described inthe present specification or during the prosecution of the application,which examples are to be construed as non-exclusive.

What is claimed is:
 1. An apparatus to be installed in an own vehicleequipped with an object detection sensor that repeatedly performs adetection operation for detecting objects around the own vehicle, theapparatus being configured to recognize, based on results of thedetection operations, a target object upon at least part of results ofthe detection operations associated with the target object satisfying arecognition condition that is predetermined, and perform at least one ofa collision avoidance operation and a damage mitigation operation forthe own vehicle with respect to the recognized target object, theapparatus comprising: an attention region defining unit configured todefine an attention region near a blocking obstacle in response to theblocking obstacle being determined to be located between the own vehicleand the target object based on the results of the detection operations;a determiner configured to determine whether the target object islocated in the attention region; an obtaining unit configured to obtain,in response to the target object being determined to be is located inthe attention region, a detection history of the target object by theobject detection sensor before the target object is determined to belocated in the attention region; a detection determiner configured todetermine, based on the obtained detection history, whether the targetobject has been captured before the target object is determined to belocated in the attention region; and an adjuster configured to relax therecognition condition in response to the target object being determinedto have not been captured before the target object is determined to belocated in the attention region.
 2. The apparatus according to claim 1,wherein the adjuster is configured to maintain the recognition conditionunchanged upon it being determined that the target object has beencaptured before the target object is determined to be located in theattention region.
 3. The apparatus according to claim 1, wherein: thedetection determiner is configured to: determine, based on the obtaineddetection history, whether a number of detections of the target objectbefore the target object is determined to be located in the attentionregion is less than a threshold number; determine that the target objecthas not been captured before the target object is determined to belocated in the attention region upon it being determined that the numberof detections of the target object before the target object isdetermined to be located in the attention region is less than thethreshold number; and determine that the target object has been capturedbefore the target object is determined to be located in the attentionregion upon it being determined that the number of detections of thetarget object before the target object is determined to be located inthe attention region is equal to or more than the threshold number. 4.The apparatus according to claim 3, further comprising: a thresholdsetter configured to set the threshold number as a function of a speedof the own vehicle.
 5. The apparatus according to claim 3, furthercomprising: a threshold setter configured to set the threshold number asa function of a relative position of the target object relative to theown vehicle.
 6. The apparatus according to claim 3, further comprising:a threshold setter configured to set the threshold number as a functionof a relative position of the target object relative to the own vehicle.7. A method applied to an apparatus to be installed in an own vehicleequipped with an object detection sensor that repeatedly performs adetection operation for detecting objects around the own vehicle, themethod recognizing, based on results of the detection operations, atarget object upon at least part of results of the detection operationsassociated with the target object satisfying a recognition conditionthat is predetermined, and perform at least one of a collision avoidanceoperation and a damage mitigation operation for the own vehicle withrespect to the recognized target object, the method comprising: definingan attention region near a blocking obstacle in response to the blockingobstacle being determined to be located between the own vehicle and thetarget object based on the results of the detection operations;determining whether the target object is located in the attentionregion; obtaining, in response to the target object being determined tobe located in the attention region, a detection history of the targetobject by the object detection sensor before the target object isdetermined to be located in the attention region; determining, based onthe obtained detection history, whether the target object has beencaptured before the target object is determined to be located in theattention region; and relaxing the recognition condition in response tothe target object being determined to have not been captured before thetarget object is determined to be located in the attention region. 8.The method according to claim 7, the method further comprising:maintaining the recognition condition unchanged upon it being determinedthat the target object has been captured before the target object isdetermined to be located in the attention region.
 9. The methodaccording to claim 7, wherein: the step of determining whether thetarget object has been captured further comprises: determining, based onthe obtained detection history, whether a number of detections of thetarget object before the target object is determined to be located inthe attention region is less than a threshold number; determining thatthe target object has not been captured before the target object isdetermined to be located in the attention region upon it beingdetermined that the number of detections of the target object before thetarget object is determined to be located in the attention region isless than the threshold number; and determining that the target objecthas been captured before the target object is determined to be locatedin the attention region upon it being determined that the number ofdetections of the target object before the target object is determinedto be located in the attention region is equal to or more than thethreshold number.
 10. The method according to claim 9, furthercomprising: setting the threshold number as a function of a speed of theown vehicle.
 11. The method according to claim 9, further comprising:setting the threshold number as a function of a relative position of thetarget object relative to the own vehicle.
 12. The method according toclaim 9, further comprising: setting the threshold number as a functionof a relative position of the blocking obstacle relative to the ownvehicle.